This isn't a fine homebuilding question by anymeans, but I can't find a swimming pool forum, so I thought I'd try here.
We took our winter cover off of our inground pool yesterday, to find a fine, bright purple "soot" on the water side of the cover and covering the entire liner and stairs where the water touches. It brushes aside easily enough but I can't get it off of the pool light and stairs completely. I'm sure that it will stain and do a real number on the cartridge filter. Our pool company is coming out tomorrow to get the filter and lines going. But so far, they are stumped about the "purple" soot. I'm wondering if when they removed the cover last spring and folded it up while it was still wet, if this may have caused damage to the black side of the cover, causing it to deteriorate. It's just a guess. Now that the cover is dry, the purple "stuff" has turned chalklike. If anyone has any thoughts or experienced this, I'd really appreciate hearing about it. Thanks!